1. Field of the Invention
This invention relates to ultrasonic endodontic dental apparatus, and more particularly to an improved endodontic tool holder and root canal irrigating apparatus adapted to be used with an ultrasonic dental handpiece for debriding root canals and for directing fluid solutions, including medicaments, along the endodontic instrument for irrigating and treating the root canal during use of the instrument. Still more particularly, the invention relates to a tool holder having means for readily exchanging tool members by pivoting an eccentric member in the holder to secure the tool member, the tool holder also preferably including a fluid irrigating passage therein for irrigating the tool member.
2. Description of the Prior Art
Ultrasonic endodontic dental appliances employed for cutting or cleaning in dental procedures are known in which a liquid, conventionally water, flows through the handpiece to cool the handpiece. Such cooling water also flows through the ultrasonically driven tool mounting head and is discharged from the head in the direction of the tool tip to irrigate and cool the work area. One such device is disclosed, for example, in U.S. Pat. No. 4,492,574 and the present invention is particularly well adapted for use in ultrasonic devices of the type disclosed in this prior patent, the disclosure of which is incorporated herein by reference and reference to which may be had for a more complete understanding of the construction and operation of such appliances.
Endodontic files used in the performance of root canal therapy are supported for axial or longitudinal ultrasonic vibration in the head and can be ultrasonically vibrated in a transverse, wave-like motion to enhance the debriding action. It is known to provide an irrigating fluid directed along an ultrasonically vibrating endodontic file longitudinally of the axis of the file to provide irrigation of the root canal while the debriding action is proceeding; however, in the known apparatus at least part of the shaft of a file that is inserted in the head is not supported by the head. Instead of supporting the entire length of the shaft that is inserted in the head, a gap is provided between the shaft and the head, near the surface of the head, as a channel for the irrigation fluid. In this known apparatus, the butt end of the shaft is clamped in the head by a set screw, which contacts a longitudinal surface of the shaft to eliminate the instability that could occur in such apparatus if the shaft of the file were only clamped at a given point. However, the file may rock if the butt of the shaft is not fully inserted in the head. Because of the tiny size of the files, the critical distance between full insertion and an insecure position is very small, and the files themselves are difficult to manipulate. Securing such files in the known apparatus is thus somewhat difficult and so a risk that the file will be inadequately supported, or will even work loose, is present. Furthermore, the proper installation of endodontic files in such apparatus is both awkward and time-consuming.